IAppFrameWork::RequestFloat

Article
06/07/2013

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Use this method to retrieve a value from a URL query string or form post variable and convert it to a floating-point value, based on the specified or default locale.

Optionally, the RequestFloat method also checks the converted number against the specified range.

Definition

HRESULT IAppFrameWork::RequestFloat(BSTRbstrName,VARIANTvtDefault,VARIANTvtMin,VARIANTvtMax,VARIANTvtLocale,VARIANT*pvtRet);

Parameters

bstrName

[in] A BSTR that contains the name of the URL query string or form post variable to retrieve.

vtDefault

[in, optional] A VARIANT that contains the value to return if the requested URL query string or form post variable is not present or contains no value. If this parameter is not supplied, the method returns NULL.

vtMin

[in, optional] A VARIANT that contains the number that specifies the low end of the range of values against which to validate the converted value. If the variant is of type VT_NULL, the vtMin parameter value is not considered in the validation process. If the converted value is less than vtMin, then NULL is returned.

vtMax

[in, optional] A VARIANT that contains the number that specifies the high end of the range of values against which to validate the converted value. If the variant is of type VT_NULL, the vtMax parameter value is not considered in the validation process. If the converted value is greater than vtMax, then NULL is returned.

vtLocale

[in, optional] A VARIANT that contains the number that identifies the locale to use to convert the value. If this value is not specified, the RequestFloat method uses the value of the Locale property of the DataFunctions object.

pvtRet

[out, retval] A pointer to a VARIANT used to return the floating-point value. If any validation fails, the return value will be NULL.

Return Values

This method returns an HRESULT indicating whether it completed successfully. See the Error Values section for more details.

Error Values

This method returns S_OK (0x00000000) to indicate success and standard COM HRESULT error values to indicate failure. For more information about standard COM errors, see Standard COM Errors. Additional information may be available using the global Err object, which can be accessed using the API function GetErrorInfo. In particular, the GetDescription method of the IErrorInfo interface may return a text description of the error.

Remarks

The pvtRet parameter points to valid data only if the method completes successfully. If any validation fails, the pvtRet parameter will be NULL.

This method converts the specified String based on the locale specified in the vtLocale parameter if the vtLocale parameter is specified; otherwise it uses the default locale found in the DataFunctions object. It validates the result of the conversion against the vtMin and vtMax parameters, if they are specified. If the validation fails this method returns NULL.

For more information about memory ownership issues related to COM property and method parameters, see Managing COM Parameter Memory.